Paper coating apparatus



July 18, 1967 c. E. WE RNER 3,331,351

PAPER COATING APPARATUS Filed Oct. 15, 1964 2 Sheets-Sheet 1 PRIOR ART/0 INVENTOR.

CHARLES E WERNER July 18, 1967 c. E. WERNER 3,331,351

I PAPER COATING APPARATUS Filed Oct. 15, 1964 2 Sheets-Sheet 2 INVENTOR.

CHARLES E WERNER United States Patent 3,331,351 PAPER COATING APPARATUSCharles E. Werner, Chillicothe, Ohio, assignor to The Mead Corporation,Dayton, Ohio, a corporation of Ohio Filed Oct. 15, 1964, Ser. No.404,119 6 Claims. (Cl. 118-70) pass a web of paper supported by arotating roll through a pool of fluent coating material and thereafterpast a trailing blade bearing on the web of material to limit thethickness of and smooth the coating applied to the web. Heretofore,various attempts have been made to provide end dams for paper coatingmachines but all such prior art devices have suffered from one or moreserious disadvantages which has in some respect limited their utility.Such prior art end dams have usually required frictional contact betweenthe edge of the end dam and the rotating surface or surfaces. Suchstructural arrangements require that the contacting surface of the enddam which engages the rotating surface have precisely the same radius ofcurvature as the rotating surface because, if this requirement is notmet, leakage of the fluent coating material will result. Furthermore, ifthe contacting surface of the end dam is of a lesser radius than therotating surface, one or more points of relatively high bearing pressurewill result so that the area of the rotating surface in contact with theend dam is subjected to abnormal wear which results in a groove beingformed on the rotating surface.

Since the conventional rotating surfaces are rolls having a'resilieutouter cover which is ground to maintain desired smoothness, relativelyfrequent changes occur in the radius of the roll so that curvature ofthe edge of the end dam, following a period of operation, no longerconforms'to the curvature of the roll, particularly after the roll hasbeen reground a number of times. Furthermore, attempts have been made tominimize the lack of good fit between the edge of the end dam and theroll surface by placing the end dams so that they engage the edge of theweb which is in turn supported by the roll. Even so, the roll surface isdeformed and grooved by the pressure of the end dam, and such groovedrolls must be reground to a smooth surface before a wider web can becoated. Additionally, the prior art arrangements have resultedindifiiculty in avoiding scoring or otherwise marking or damaging of thecoated sheet.

Accordingly, a principal object of the present invention is to provideimproved means for overcoming the abovenoted deficiencies anddifliculties.

It is a further object of the invention to provide an end dam sealingstructure that will provide maximum flexibility in the width of thepaper web to be coated.

Still another object of the invention is to provide an arrangementwhereby the end dams are mounted independently of the coating headassembly with resilient backed sealing means to permit blade adjustmentwithout requiring a concurrent end dam adjustment.

A further object is in the provision of an improved arrangement forachieving a positive seal between the coating head and the roll in suchamanner and at such a location that destructive wear of the roll and thesealing elements is minimized.

Still another object of the invention is in the provision of an improvedmeans for containing the color in the puddle of a puddle type bladecoater which employs only elements that are mechanically simple and easyto manufacture and install, and at the same time, avoids operationaldifficulties which may arise from the tendency for dried color to buildup on the face of the roll and in the sealing apertures.

Other objects and advantages will become apparent from the followingdescription taken in connection with the accompanying drawings in which:

FIGURE 1 is a diagrammatic plan view of an end dam illustrating priorart devices;

FIGURE 2 is a diagrammatic pli-an view illustrating one L embodiment ofthe end dam of the present invention;

FIGURE 3 is an enlarged plan view partly broken away of the embodimentof FIGURE 2;

FIGURE 4 is an enlarged side elevation partly broken away of theembodiment of FIGURE 2; and,

FIGURE 5 is an enlarged plan view partly broken away illustrating analternative embodiment of the invention.

Referring now to the drawings, in FIGURE 1, a web 10 of paper,paperboard or the like, is led downwardly over a roll 11 which has aresilient cover 12. A coating head 13 carrying a blade 14 is mounted sothat the blade tip engages the surface of the web 10.

End dams 16 16, of the type used prior to this inventron, are rigidlymounted on the coater head 13 andshaped to conform to the curvature ofthe resilient surface 12 of roll 11. End dams 16-16 are positioned toengage the edges of web 10, and are intended to retain the fluentcoating material in the trough formed by the web on the backing roll,the blade and the coating head.

One embodiment of the improved end dam of this invention is ilustratedin FIGURE 2. The general features of Web 10 supported by resilientmember 12, backing roll 11 and moving past the tip of blade 14 which ismounted on coating head 13 are the same as illustrated in FIGURE 1.Again referring to FIGURES 2 and 3, the end dams 17 of the presentinvention are mounted on brackets 15 to a part of the machine frame (notshown) and are positioned adjacent the ends of roll 11. The front edgeof the end dams is curved to generally conform to the curvature of rollsurface 12, as is best illustrated in FIGURE 4. The positioning of theend dam 17 at the ends of roll 11 permit the operation of the coaterwith any desired width of web, up to the limit of the spacing betweenthe end dams, without requiring a change in the location of the enddams. Contrary to expectations, it has been found that no new problemsare introduced by contact of the pool of fluent coating material withthe resilient surface 12 of roll 11 in areas not covered by Web 10. Thefluent coating material acts as a lubricant to minimize wear of the rollsurface by the blade tip and leakage of coating material at the edges ofthe web is prevented by a small line or band of coating material whichdries on the face of the roll. If this dried coating materialaccumulates to an objectionable amount, a small water spray directedonto the dried coating on the roll surface will control or eliminateexcessive accumulation of such material. The absence of sealing surfacesbearing on the edges of the paper web greatly reduces the incidence ofweb brakes causd by wrinkles and cracked or torn edges, thus provid ingsignificantly more eflicient operation of the coating machine.

As noted heretofore, it is desirable to provide a positive seal betweenthe coating head and the roll and at the same time to avoid unduepressure against the resilient cover 12 which results in excessive wearand grooving of the resilient cover. In accordance with the presentinvention, this is achieved by causing a resilient member to sealagainst a seal plate mounted closely adjacent the opposite ends of roll11 and with pressure exerted by the resilient sealing material againstthe resilient cover 12 confined to an extremely small area at each endof roll 11 so that no appreciable wear of the usable surface ofresilient cover 12 is encountered.

Each of the end dams 17 comprises a support member 18, resilient sealingmaterial 19, and a seal plate member 20. One of these end dams will nowbe described in greater detail and it is to be understood that suchdescription applies equally to the other darn which is disposed at theopposite end of roll 11.

Support member 18 is detachably connected to coating head 13 by anyknown means. Conveniently, threaded fastening means may be employed toeffect the connection between coating head 13 and support member 18.Support member 18 extends outwardly from coating head 13 in a directiongenerally toward the outer resilient surface 12 of roll 11 andterminates somewhat short thereof. A illustrated in FIGURE 2, one sideof face 24 of support member 18 is substantially aligned with and liesgenerally in a plane which includes the end face of roll 11.

A seal plate member 20 is adjustably connected to bracket which bracketis connected to a portion of the machine frame (not shown). The meansemployed for effecting such connection between sealing plate and bracket15 will be described in greater detail as the description proceeds. Forpresent purposes, it will be sufficient to state that the adjustableconnecting means permits the placing and maintaining of seal platemember 20 in a desired location relative to roll 11 and support member18.

Seal plate member 20 is a plate like member having spaced apart opposedfaces 21, 22 which are substantially parallel. Interposed between faces21, 22 is a face portion 23 that is also substantially parallel to faces21, 22. In the drawing, face 1 extends to the left from the right handend of seal plate member 20 while face portion 23 extends to the rightfrom the left hand portion of seal plate member 20. Face 21 and faceportion 23 are each shorter in length than face 22 and are connectedtogether by a wall 24 that is angularly disposed relative to thesubstantially parallel plane surfaces of face 21 and face portion 23.When installed for operation, sealing plate member 20 is maintained bybracket 15 in such position that faces 21, 22 and face portion 23 aresubstantially parallel With the end face of roll 11 with face 21positioned closely adjacent the end face ofroll 11 with sufficientclearance space so as to avoid mechanical interference with theseelements during rotation of roll 11. It will be appreciated that when insaid position, face 21 of sealing plate 20 lies within or issubstantially within and closely spaced from and parallel to a planecontaining the outer face 25 of support member 18. Hence, face portion23 of seal plate member 20 is spaced apart from and substantiallyparallel to the outer face 25 of support member 18. Disposed in thespace between face member 23 and the outer face 25 is resilient sealingmaterial 19 having a front edge portion that is curved to conformgenerally with the curvature of resilient surface 12. Sealing material19 is secured in any convenient manner to support member 18. Forexample, threaded fastening means 26 may be employed to connect thesealing material 19 to support member 18. interposed between the backedge of member 18 and the coating head 13 is resilient sealing material27 for effecting a liquid tight seal between the member 18 of end dam 17and coating head 13. Material 27 may be rubber sheeting, sponge rubberor the like. Accordingly, relatively small movement of coating head 13and blade 14 toward roll 11 to compensate for wear of the blade tip doesnot require repositioning or readjustment of the end dams.

It is to be noted that when coating head 13 is in operating position,the forward edge portion of the resilient sealing material 19 extendsradially inward along the end face of roll 11 byond the outer resilientsurface 12. Attention is also directed to the fact that as the coatinghead 13 is advanced toward roll 11 into operating position the forwardedge portion of material 19 begins to engage the angularly disposedportion 24 of seal plate member 20 thus producing a force in a directionparallel to the axis of rotation of roll 11 that tends to press theresilient sealing material 19 between the outermost portion of the endface of roll 11 and faces 23 and 24 of seal plate member 20 thus sealingand confining the fluent material which is confined in the space betweencoating head 13, outer surface 12 of roll 11 and also between end dams17-17 which are disposed at opposite ends of the roll. Thus, it will beseen that any sealing pressure exerted upon roll 11 is exerted in adirection parallel to rather than normal to the axis of rotation thereofand is applied to the end faces of the roll and not against theresilient cover surface 12 upon which the web 10 is carried.

In the alternative embodiment of the end dams 17-17 illustrated inFIGURE 5, the same structural elements are employed as in the case ofthe embodiment of FIG- URE 3 but the relative positions of the elementsare modified somewhat. In the alternative embodiment, the forward edgeportion of resilient sealing material 19, as well as the inclined face24 of sealing plate member 20, are moved relatively to the left from theposition illustrated in FIGURE 3 so that sealing material 19 is urged byinclined face 24 into engagement with not only the end face of roll 11but a portion of the sealing material also contacts the outed surface ofresilient cover 12. Such contact of the outer surface 12 by the sealingmaterial is confined to a very small area closely adjacent the cornerformed by the intersection of the end face of roll 11 and the resilientcover 12 so that if any grooving or other destructive effect of thepressure of the sealing material on the resilient cover does result,such grooving is confined to a very small area at the oppositeextremities of the cover and such effects are confined to extremelysmall areas which are remote from web 10 and do not fall within theusable surface of resilient cover 12.

Based on information and operating experience presently available, theembodiment illustrated in FIGURE 3 generally is considered the preferredembodiment but experience also has shown that the alternative embodimentillustrated in FIGURE 5 not only provides a satisfactory seal but incertain instances the alternative embodiment may be more desirablyemployed than the embodiment of FIGURE 3.

Irrespective of whether it is desired to employ the embodiment of FIGURE3 or that of FIGURE 5, a plurality of jack screws 28, 29 are employed toadjustably connect the sealing plate member 20 to bracket 15. The jackscrews 23, 29 provide sufficient flexibility to permit plate member 20to be positioned closely adjacent the end face of roll 11 and at thesame time permit whatever adjustment may be necessary in order to assurethe desired degree of parallelism between the end face of roll 11 andfaces 21, 22 and 23.

When prior art end dams have been used in connection with a puddle typeblade coater for containing the color in the puddle, operatingdifficulties have been quite severe due to the tendency for driedcoating color to build up on the face of the roll and in the sealingpassageways thus interfering with the collecting system and causingcolor to be thrown from the face of the roll. In accordance with thepresent invention, this difiiculty is avoided because the seal plate ispositioned in close proximity to the end face of the roll. Also, aconduit 30 provides a small supply of water to the aperture between face21 of seal plate member 20 and the end face of roll 11 so that the endof the roll remains clean and color throw-off is avoided.

Thus, it will be seen that the invention provides an effective end damseal which provides maximum flexibility and operation with reference tothe width of web to be handled, employs structural elements which aremechanically simple, does not require precise dimensions of the sealingmaterial, and provides effective sealing without destructive action onthe usable outer surface of the roll.

While particular embodiments of the invention have been illustrated anddescribed, it will be obvious to those skilled in the art that variouschanges and modifications can be made without departing from theinvention, and it is intended in the appended claims to cover all suchchanges and modifications that fall within the true spirit and scope ofthe invention.

What is claimed is:

1. In an apparatus providing a reservoir for supplying fluent coatingmaterial to a roll-carried sheet, the combination comprising a coatingroll provided with a resilient surface; a coating head; and end damsshaped to conform to the curvature of the said resilient surface of saidroll and positioned at each end of said rolls to form a reservoir withsaid roll, each of said end dams comprising a support member detachablyconnected to said coating head and extending outwardly therefrom, a sealplate member provided with a chamfered surface and mounted closely tothe ends of said roll, and a resilient sealing member, said resilientsealing member being secured to said support member and positionedbetween said chamfered sealing plate and said roll in such a manner thatthe leading edge of said resilient sealing member is urged by saidchamfered surface into engagement with said roll end and thereby sealingsaid reservoir.

2.. The combination of claim 1 including means for urging the platemember toward the end faces of said roll.

3. The combination of claim 2 wherein said urging means includes amember spaced from and disposed in close proximity with the end face ofsaid roll, and including means including conduit means for supplying asolvent to the space between the end face of said roll and said closelyspaced member.

4. The combination of claim 1 wherein said sealing means is urged partlyin a radial direction against the cylindrical outer surface of said rolland partly in an axial direction against the end face of said roll.

5. In an apparatus providing a reservoir for supplying fluent coatingmaterial to a roll-carried sheet comprising a coating roll provided witha resilient surface, a coating head, end dams shaped to conform to thecurvature of the resilient surface of said roll and positioned at eachend of said roll to form a reservoir with said roll, the improvementwhich comprises providing for each of said end dams a support memberdetachably connected to the said coating head and extending outwardlytherefrom, a seal plate member provided with a chamfered surface andmounted closely to the ends of said roll, and a resilient sealing membersecured to said support member and positioned between said chamferedsealing plate and said roll in such a manner that the leading edge ofsaid resilient sealing member is urged by said chamfered surface intoengagement with said roll and thereby sealing said reservon.

6. The combination of claim 5 wherein said sealing means is urged partlyin a radial direction against the cylindrical outer surface of said rolland partly in an axial direction against the end face of said roll.

References Cited UNITED STATES PATENTS 2,105,981 1/1938 Massey et a1.118203 X 2,281,588 5/1942 Magnus 118-259 X 2,918,899 12/1959 Munton eta1. 118-413 3,097,968 7/ 1963 Schaefer 118259 3,169,082 2/ 1965Krikorian 118413 3,179,536 4/1965 Martinek 118-40 7 X CHARLES A.WILLMUTH, Primary Examiner. J. P. MCINTOSH. Assistant Examiner.

1. IN AN APPARATUS PROVIDING A RESERVIOR FOR SUPPLYING FLUENT COATINGMATERIAL TO A ROLL-CARRIED SHEET, THE COMBINATION COMPRISING A COATINGROLL PROVIDED WITH A RESILIENT SURFACE; A COATING HEAD; AND END DAMSSHAPED TO CONFORM TO THE CURVATURE OF THE SAID RESILIENT SURFACE OF SAIDROLL AND POSITIONED AT EACH END OF SAID ROLLS TO FORM A RESERVOIR WITHSAID ROLL, EACH OF SAID END DAMS COMPRISING A SUPPORT MEMBER DETACHABLYCONNECTED TO SAID COATING HEAD AND EXTENDING OUTWARDLY THEREFROM, A SEALPLATE MEMBER PROVIDED WITH A CHAMFERED SURFACE AND MOUNTED CLOSELY TOTHE ENDS OF SAID ROLL, AND A RESILIENT SEALING MEMBER, SAID RESILIENTSEALING MEMBER BEING SECURED TO SAID SUPPORT MEMBER AND POSITIONEDBETWEEN SAID CHAMFERED SEALING PLATE AND SAID ROLL IN SUCH A MANNER THATTHE LEADING EDGE OF SAID RESILIENT SEALING MEMBER IS URGED BY SAIDCHAMFERED SURFACE INTO ENGAGEMENT WITH SAID ROLL END AND THEREBY SEALINGSAID RESERVOIR.